1. Field of the Invention
The present invention relates to a composition for forming an aluminum-containing film, and a method for forming an aluminum-containing film.
2. Discussion of the Background
Because of its density and excellent insulating properties, aluminum oxide (alumina) is widely used as a protective film and an insulating film in dynamic random access memory (DRAM) and other semiconductor devices. Other applications are being studied, including gap layers and protective films for thin-film magnetic heads, protective films for metal parts, and gas barrier films on plastic films and the like.
Meanwhile, because of its high thermal conductivity and insulating properties, aluminum nitride is being studied for use as a heat-dissipating substrate in semiconductor devices, and also holds promise as an optical material.
Conventionally, sputtering and chemical vapor deposition methods have been widely used as methods for forming aluminum oxide and aluminum nitride.
For example, Japanese Patent Application Publication No. H9-316631 proposes a method for forming an aluminum oxide film by sputtering an aluminum-containing target in a gas containing fluorine atoms.
On the other hand, Japanese Patent Application Publication No. 2001-220294 proposes a film-forming method in which atomic layer epitaxial growth methods are used to form an insulating film formed of alternating layers of aluminum oxide and titanium oxide.
Meanwhile, Japanese Patent Application Publication (Translation of PCT Application) No. 2006-526705 proposes a method for forming an aluminum-containing film (aluminum oxide film, aluminum nitride film or aluminum oxynitride film) on a substrate by CVD using a non-pyrophoric amino aluminum precursor.
In contrast with the aforementioned film-forming methods, a target film can be obtained more easily and with less expensive equipment by using coating methods, in which an aluminum-containing film is obtained by coating and heat-treating a solution of an aluminum-containing compound or polymer as a raw material on a substrate. It is expected that these coating methods will be widely used in the future because they are superior from the standpoint of embedding properties, step coverage and film formation on narrow-trench substrates.
As an example of a coating method, Japanese Patent Application Publication No. 2007-210825 proposes a method for manufacturing an alumina film by coating a compound having an Al—N bond on its skeleton or a solution of this compound on a substrate, and heating it at a temperature range of 50 to 1000° C. in an atmosphere containing an oxygen-containing gas, and describes, as an example of the solution of the compound having an Al—N bond on its skeleton, an example using a solution of an imino alane dissolved in an organic solvent as a composition for forming a film.